Selecting points on an electroanatomical map

ABSTRACT

Described embodiments include a system that includes a display and a processor. The processor is configured to position an indicator, in response to a positioning input from a user, over a particular point on a three-dimensional electroanatomical map that is displayed on the display, and over which are displayed a plurality of markers that mark respective data points. The processor is further configured to expand a contour, subsequently, along a surface of the map, while a selecting input from the user is ongoing, such that all points on the contour remain equidistant, at an increasing geodesic distance with respect to the surface, from the particular point, and to display, on the display, one or more properties of each of the data points that is marked by a respective one of the markers that is inside the contour. Other embodiments are also described.

FIELD OF THE INVENTION

The present invention relates to methods and interfaces for interactingwith computer-rendered models, such as computer-rendered models ofanatomical surfaces.

BACKGROUND

Three-dimensional surfaces are often represented in computer memory by acontiguous collection of tiles, such as triangular tiles. Such arepresentation may be referred to as a “tesselation” or a “mesh.”

A “geodesic distance,” with respect to a given surface, between twopoints that lie on the surface, is the length of the shortest path,along the surface, that connects the two points. For points lying on acurved surface, this distance is often different from the Euclideandistance between the points. For example, the geodesic distance betweentwo hilltops is the length of the shortest path that runs, along thesurface of the Earth, between the two hilltops. This distance is largerthan the Euclidean distance between the hilltops, which is the length ofa straight path, through the air, passing between the hilltops.

SUMMARY OF THE INVENTION

There is provided, in accordance with some embodiments of the presentinvention, a system that includes a display and a processor. Theprocessor is configured to position an indicator, in response to apositioning input from a user, over a particular point on athree-dimensional electroanatomical map that is displayed on thedisplay, and over which are displayed a plurality of markers that markrespective data points. The processor is further configured to expand acontour, subsequently, along a surface of the map, while a selectinginput from the user is ongoing, such that all points on the contourremain equidistant, at an increasing geodesic distance with respect tothe surface, from the particular point, and to display, on the display,one or more properties of each of the data points that is marked by arespective one of the markers that is inside the contour.

In some embodiments, the indicator includes a cursor.

In some embodiments, the selecting input includes a click of a button ofa mouse.

In some embodiments, the processor is further configured to display thecontour on the display while expanding the contour.

In some embodiments, the electroanatomical map includes anelectroanatomical map of a surface of a heart.

In some embodiments, the one or more properties include one or moreelectrical properties.

In some embodiments, the processor is further configured to set a speedof expansion of the contour, in response to a speed-indicating inputfrom the user.

In some embodiments, the processor is configured to expand the contourwith a varying speed of expansion.

In some embodiments, the processor is configured to vary the speed ofexpansion as a function of a number of the markers that are within agiven area that lies ahead of the contour.

In some embodiments, the processor is configured to vary the speed ofexpansion as a function of a density of the markers that are within agiven area that lies ahead of the contour.

There is further provided, in accordance with some embodiments of thepresent invention, a method that includes, using a processor, inresponse to a positioning input from a user, positioning an indicatorover a particular point on a displayed three-dimensionalelectroanatomical map over which are displayed a plurality of markersthat mark respective data points. The method further includes,subsequently, while a selecting input from the user is ongoing,expanding a contour along a surface of the map, such that all points onthe contour remain equidistant, at an increasing geodesic distance withrespect to the surface, from the particular point, and displaying one ormore properties of each of the data points that is marked by arespective one of the markers that is inside the contour.

The present invention will be more fully understood from the followingdetailed description of embodiments thereof, taken together with thedrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a system for selecting data pointsin a three-dimensional electroanatomical map, in accordance with someembodiments of the present invention;

FIG. 2 is a schematic illustration of a method, performed by aprocessor, for selecting data points in a three-dimensionalelectroanatomical map, in accordance with some embodiments of thepresent invention;

FIG. 3 is a schematic cross-section through a surface of anelectroanatomical map on which a contour is located, in accordance withsome embodiments of the present invention; and

FIG. 4 is a flow diagram for a method for selecting data points, whichis executed by a processor in accordance with some embodiments of thepresent invention.

DETAILED DESCRIPTION OF EMBODIMENTS Overview

In some embodiments, an electroanatomical map of a subject's heart isconstructed. As implied by the word “electroanatomical,” such a mapcombines anatomical information relating to the structure of the heartwith information relating to the electrical activity of the heart. Forexample, the map may include a three-dimensional mesh, representing asurface of the heart, that is colored (or otherwise annotated) inaccordance with local activation times (LATs), electrical potentials,and/or other properties that were measured at various locations on thesurface. Such a mesh is typically constructed from a large number ofdata points, each of which corresponds to a particular location on thesurface of heart at which the property of interest was measured. Themesh may be rendered on screen, with a plurality of markers indicatingthe respective locations of the data points.

In some cases, a user may wish to investigate, discard, edit, orotherwise process a cluster of data points located in a particularregion of interest. To do this, the user must first select the relevantdata points, by selecting the corresponding markers on the screen.However, performing such a selection may be tedious, particularly if theregion of interest contains a large number of data points. For example,traditional “point-and-click” techniques require that the userseparately click on each of the markers that corresponds to a data pointof interest.

Embodiments of the present invention therefore provide improvedtechniques for selecting data points belonging to an electroanatomicalmap. In some embodiments, the user performs an extended mouse click,i.e., the user holds a mouse button in a clicked position, over aparticular point of interest on the map. As the click is held, a contourexpands outward from the particular point, such that all points on thecontour remain equidistant, at an increasing geodesic distance, from theparticular point. As the contour expands, the contour encapsulates anymarkers that it crosses, thus selecting the corresponding data points.When the user releases the mouse button, the contour stops expanding,and properties of all of the selected data points are displayed. In thismanner, a large number of data points may be selected relativelyquickly.

Moreover, by virtue of all points on the contour being geodesicallyequidistant from the point of interest, the selection of data points asdescribed above is precise, i.e., the selection generally achieves aresult that is similar to that which would have been achieved had theuser manually clicked on all of the markers in the user's region ofinterest. This is because the geodesic distance between two points onthe surface of the heart is generally correlated to the amount of timerequired for bioelectric signals to propagate between the two points,since such signals travel along the surface of the heart. Since,typically, a user (such as an electrophysiologist) would like to selecta groups of data points that are within a particular propagation time ofa point of interest, selecting data points according to their geodesicdistance from the point of interest achieves the user's objective.

In other embodiments, the user is provided with a virtual brush, whichthe user may move across the display, e.g., using a mouse. As the brushmoves over markers that are displayed on the map, the corresponding datapoints are selected.

It is noted that embodiments described herein may be applied to theselection of points of any type, belonging to any sort of threedimensional model that is rendered on screen.

Alternatively, embodiments described herein may be used to identify aregion of the model that is within a particular geodesic distance of apoint of interest, without necessarily performing any point selection.

(It is noted that a contour is said to be at a particular geodesicdistance from a point of interest on a map of an anatomical surface, ifthe contour is superimposed over the set of points on the map thatcorrespond, respectively, to locations on the anatomical surface thatare at the particular geodesic distance from the location on theanatomical surface to which the point of interest corresponds.)

System Description

Reference is initially made to FIG. 1, which is a schematic illustrationof a system 20 for selecting data points in a three-dimensionalelectroanatomical map, in accordance with some embodiments of thepresent invention. System 20 comprises a processor 22 and a display 24,and may further comprise one or more input devices, such as a mouse 26and/or a keyboard 28.

As shown in FIG. 1, processor 22 may display, on display 24, athree-dimensional electroanatomical map 30, such as a map of a surfaceof a subject's heart. As described above, electroanatomical map 30 maybe constructed from a plurality of data points, each of which may bemarked by a respective marker 32 displayed over the electroanatomicalmap. As described in detail below, a user may use display 24, mouse 26,keyboard 28, and/or any other input device to interact with theelectroanatomical map. For example, as described below, the user may usethe mouse to expand a contour 34 along the surface of theelectroanatomical map, thus selecting a plurality of data points.

In general, processor 22 may be embodied as a single processor, or as acooperatively networked or clustered set of processors. Processor 22 istypically a programmed digital computing device comprising a centralprocessing unit (CPU), random access memory (RAM), non-volatilesecondary storage, such as a hard drive or CD ROM drive, networkinterfaces, and/or peripheral devices. Program code, including softwareprograms, and/or data are loaded into the RAM for execution andprocessing by the CPU and results are generated for display, output,transmittal, or storage, as is known in the art. The program code and/ordata may be downloaded to the processor in electronic form, over anetwork, for example, or it may, alternatively or additionally, beprovided and/or stored on non-transitory tangible media, such asmagnetic, optical, or electronic memory. Such program code and/or data,when provided to the processor, produce a machine or special-purposecomputer, configured to perform the tasks described herein.

Reference is now made to FIG. 2, which is a schematic illustration of amethod, performed by processor 22, for selecting data points in athree-dimensional electroanatomical map, in accordance with someembodiments of the present invention.

First, as shown in the left portion of FIG. 2, processor 22 receives apositioning input 36 from the user. For example, as illustrated in FIG.2, positioning input 36 may include a movement of mouse 26. In responseto positioning input 36, the processor positions a cursor 39 over aparticular point on the displayed three-dimensional electroanatomicalmap, per the positioning input. Alternatively, the processor may receiveany other suitable type of positioning input (e.g., a pressing of arrowkeys on keyboard 28, or suitable gestures performed on a touch-screen ofdisplay 24), and, in response thereto, position cursor 39, or any othersuitable indicator, over the particular point indicated by thepositioning input.

Subsequently, the user begins a selecting input 38, e.g., by clicking abutton of mouse 26, or by pressing a key on keyboard 28. Then, as shownin the middle portion of FIG. 2, while selecting input 38 is ongoing(e.g., while the mouse-button click is held), the processor expandscontour 34 along a surface of the electroanatomical map, such that allpoints on the contour remain equidistant, at an increasing geodesicdistance D_(G) with respect to the surface, from the particular point 40at which the cursor was positioned. Typically, the processor displaysthe contour while expanding the contour. In some embodiments, while thecontour is expanding, the user may rotate the electroanatomical map,zoom in to or out from the electroanatomical map, or otherwise adjusthis view of the electroanatomical map.

As the selecting input is held, the processor repeatedly re-computes thecontour at an increased geodesic distance from the point of interest.Geodesic distances may be computed using any suitable techniques knownin the art, such as Dijksta's algorithm, or the fast marching method,described in Sethian, James A., “A fast marching level set method formonotonically advancing fronts,” Proceedings of the National Academy ofSciences 93.4 (1996): 1591-1595, which is incorporated herein byreference.

In some embodiments, the speed at which contour 34 is expanded remainsfixed during the expansion of the contour. This speed may be set by theprocessor in response to a speed-indicating input from the user. Forexample, the user may enter a desired contour-expansion speed usingkeyboard 28. In other embodiments, the speed of expansion varies duringthe expansion of the contour. For example, the speed of expansion mayincrease as the contour grows larger, and/or may vary as a function ofthe number and/or density of markers within a given area that lies aheadof the contour. Thus, for example, the contour may expand more quicklyinto areas of the map that contain relatively few markers, and lessquickly into areas of the map that contain more markers. In suchembodiments, an initial speed of expansion, a rate of acceleration ofexpansion, and/or any other relevant parameters of the expansion may beset by the processor in response to input from the user.

Finally, as shown in the right portion of FIG. 2, selecting input 38ends. In response to the end of the selecting input, the processor stopsthe expansion of contour 34.

Following the end of the expansion of the contour, the processordisplays one or more properties of each of the data points that ismarked by a respective one of markers 32 that is inside the contour.Alternatively or additionally, the processor may display theseproperties as the contour is expanding. For example, each time thecontour passes, and hence encapsulates, another one of the markers, theprocessor may display the properties of the data point that is marked bythe newly-encapsulated marker.

Reference is now made to FIG. 3, which is a schematic cross-sectionthrough a surface 41 on which contour 34 is located, in accordance withsome embodiments of the present invention.

The cross-section of FIG. 3 “cuts through” contour 34 at two points: afirst contour-point 42 a, and a second contour-point 42 b. As notedabove, all of the points on contour 34 are at an equal geodesic distancefrom point 40. Thus, first contour-point 42 a and second contour-point42 b are shown lying at an equal geodesic distance D_(G) from point 40.To avoid any confusion, it is emphasized that a geodesic distancebetween two points is measured along the surface on which the pointslie, and may therefore be different from the Euclidean distance betweenthe points. For example, in FIG. 3, the Euclidean distance D_(E1)between point 40 and second contour-point 42 b is less than theEuclidean distance D_(E2) between point 40 and first contour-point 42 a,despite these points being at an equal geodesic distance from point 40.

In general, as noted above in the Overview, the geodesic distancebetween two points on the surface of the heart is correlated to theamount of time required for bioelectric signals to propagate between thetwo points, since such signals travel along the surface of the heart.Hence, geodesic distance corresponds to the manner in which a typicaluser (such as an electrophysiologist) thinks of “distance” betweenpoints on the surface of the heart. The selection of data points usingcontour 34 thus generally achieves a result that is similar to thatwhich would have been achieved had the user manually clicked on all ofthe markers in the user's region of interest.

As noted above, each of the data points in electroanatomical map 30 mayinclude various properties, such as electrical properties, of thesurface of heart. Following the selection of the data points, theprocessor displays, on display 24, one or more of these properties, foreach of the selected data points. For example, the processor may displaya respective LAT and/or electrical potential of each of the selecteddata points. Alternatively or additionally, such properties may bedisplayed in “real-time,” as the contour is expanding, for each datapoint encapsulated by the contour.

Reference is now made to FIG. 4, which is a flow diagram for a method 43for selecting data points, which is executed by processor 22 inaccordance with some embodiments of the present invention. In general,most of the steps of method 43 were already described above, but arenonetheless described again, in brief, below, with reference to FIG. 4.

First, at a model-displaying step 44, the processor displays athree-dimensional model, such as the electroanatomical map describedabove. The processor then, at a positioning-input-receiving step 46,receives a positioning input from a user. In response thereto, theprocessor, at a positioning step 48, positions an indicator over aparticular point on the model, as indicated by the positioning input.Next, at a selecting-input-receiving step 50, the processor receives aselecting input from the user. In response thereto, at acontour-expanding step 52, the processor expands a contour outward,along the surface of the model, from the particular point, such that allpoints on the contour remain equidistant, at an increasing geodesicdistance, from the point. While expanding the contour, the processorcontinually checks, at a checking step 54, whether the selecting inputis ongoing. If yes, the processor continues expanding the contour.Otherwise, at a stopping step 56, the processor stops expanding thecontour. Finally, at a property-displaying step 58, the processordisplays the properties of the selected data points. (As noted above,property-displaying step 58 may be executed earlier, while the contouris expanding.)

In other embodiments, the user is provided with a virtual brush, whichthe user then passes over the model, e.g., by dragging the brush withmouse 26. As the brush passes over the model, data points marked by themarkers over which the brush passes are selected. In some embodiments,the processor colors, shades, or otherwise marks portions of the modelover which the brush has passed, and/or enlarges or otherwise changesthe form of markers 32 over which the brush has passed, to indicate tothe user the data points that have been selected. While passing thebrush over the model, the user may rotate the model, zoom in to or outfrom the model, or otherwise adjust his view of the model.

The processor typically positions the brush above, or in front of, themodel, relative to the perspective of the user who is viewing the screenof display 24. As the user moves the brush across the model, theprocessor projects a virtual three-dimensional object from the brush“into” the screen, such that the object intersects the surface of themodel. The processor identifies the area of the surface over which theintersection occurs, and then selects any data points whose markers arewithin this area. For example, as the user moves a circular brush acrossthe screen, the processor may compute the area over which a virtualcylinder projected from the brush intersects the surface of the model,and may then select any data points whose markers are within this area.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed hereinabove. Rather, the scope of embodiments of the presentinvention includes both combinations and subcombinations of the variousfeatures described hereinabove, as well as variations and modificationsthereof that are not in the prior art, which would occur to personsskilled in the art upon reading the foregoing description. Documentsincorporated by reference in the present patent application are to beconsidered an integral part of the application except that to the extentany terms are defined in these incorporated documents in a manner thatconflicts with the definitions made explicitly or implicitly in thepresent specification, only the definitions in the present specificationshould be considered.

1. A system, comprising: a display; and a processor, configured: toposition an indicator, in response to a positioning input from a user,over a particular point on a three-dimensional electroanatomical mapthat is displayed on the display, and over which are displayed aplurality of markers that mark respective data points; to expand acontour with a varying speed of expansion as a function of (i) a numberof the markers that are within a given area that lies ahead of thecontour, or (ii) a density of the markers that are within a given areathat lies ahead of the contour, subsequently, along a surface of themap, while a selecting input from the user is ongoing, such that allpoints on the contour remain equidistant, at an increasing geodesicdistance with respect to the surface, from the particular point; and todisplay, on the display, one or more properties of each of the datapoints that is marked by a respective one of the markers that is insidethe contour.
 2. The system according to claim 1, wherein the indicatorincludes a cursor.
 3. The system according to claim 1, wherein theselecting input includes a click of a button of a mouse.
 4. The systemaccording to claim 1, wherein the processor is further configured todisplay the contour on the display while expanding the contour.
 5. Thesystem according to claim 1, wherein the electroanatomical map includesan electroanatomical map of a surface of a heart.
 6. The systemaccording to claim 5, wherein the one or more properties include one ormore electrical properties.
 7. The system according to claim 1, whereinthe processor is further configured to set a speed of expansion of thecontour, in response to a speed-indicating input from the user. 8.(canceled)
 9. (canceled)
 10. (canceled)
 11. A method, comprising: usinga processor, in response to a positioning input from a user, positioningan indicator over a particular point on a displayed three-dimensionalelectroanatomical map over which are displayed a plurality of markersthat mark respective data points; subsequently, while a selecting inputfrom the user is ongoing, expanding a contour along a surface of the mapwith a varying speed of expansion, wherein the speed of expansion variesas (i) a function of a number of the markers that are within a givenarea that lies ahead of the contour; or (ii) a function of a density ofthe markers that are within a given area that lies ahead of the contour,such that all points on the contour remain equidistant, at an increasinggeodesic distance with respect to the surface, from the particularpoint; and displaying one or more properties of each of the data pointsthat is marked by a respective one of the markers that is inside thecontour.
 12. The method according to claim 11, wherein the indicatorincludes a cursor.
 13. The method according to claim 11, wherein theselecting input includes a click of a button of a mouse.
 14. The methodaccording to claim 11, further comprising displaying the contour whileexpanding the contour.
 15. The method according to claim 11, wherein theelectroanatomical map includes an electroanatomical map of a surface ofa heart.
 16. The method according to claim 15, wherein the one or moreproperties include one or more electrical properties.
 17. The methodaccording to claim 11, further comprising setting a speed of expansionof the contour, in response to a speed-indicating input from the user.18. (canceled)
 19. (canceled)
 20. (canceled)